i just purchased a 02 silverado ext cab z71 w/ a 5.3L and i was wondering if its possible to get an LS1 or LS2 bottom end with the 5.3 top end (heads intake etc...) to increase the cubic inches has anyone done this???

I know everyone is thinking "why wouldnt he get an LS1 or 2 and put it in his car??" but i was just thinking i could get more towing capacity and power with the truck and then id have a 5.3 bottom end for when i get more money to do a swap in the car and just have to piece the rest together cause im not rich yet

 

Ls1 bottom end will fit if you pull the internals out and have the cylinders bored to the correct size. Only two major parts you need are rods and pistons since the cranks are the same on the 5.3s and above.

LS2 internals won't fit due to the larger bore. They would fit in the 6 liter blocks but there's really no need to as it doesn't gain you much.

My advice would be to get a set of stock ls1 rods and then a set of aftermarket ls1 pistons. This way you end up with a bottom end that can hold up to anything.

 

so i cant just bolt up the ls1 shortblock?

 

you can remove your shortblock and put a ls1 shortblock under it, or there's a sponsor on ls1tech who sells 5.3L shortblocks bored out to ls1 piston bores and sells them complete brand new for $1600 IIRC. Honestly just do some headers and an intake along with a few supporting mods and it'll make more power for less.

 

yeah i know the bolton route is easiest but then id have nothing for my bird

 

Well, first off.... a shortblock is exactly that....a block with crank, rods, pistons, cam, lifters...pretty much everything but the heads, intake and accessories. To bolt up an LS1 shortblock in your 'bird the same way you would do a 5.3.

Now if you are asking if you can put an LS1 rotating assembly in a 5.3 you have the cylinders bored for the LS1 pistons.

 

... i dont want to "build" a shortblock using my block, nor do i wish to purchase a rebuilt one for over a grand... my plan is to have my junk dealer find an LS1 shortblock for pretty cheap to increase the cubic inches on my truck... then keep the left over 5.3 "shortblock" for use in my bird later on.
maybe i will have the 5.3 built with an LS1 bore and low compression for use with a supercharger in the bird but for the truck i wanna get more power and tq cheap, and have parts left over for the bird
if i just buy headers and boltons for the truck... the bird will have no hand me downs...
i basically did this post because i was not aware if the 5.3 heads and LS1 block would work together and vice versa, but after everyones help here, and a little more research ive found my answer...
next question, which Factory "LS" heads flow best?? and are they all interchangeable as long as you start with an LS engine... such as LS1 LS2 LS6 LS7 LQ9 etc... and is there a code for the 5.3??

 

You're thinking too small.

You can get a complete LQ4 6.0l for next to nothing. Unbolt the 5.3, bolt in the 6.0.

 

now thats what im talking about... the LQ9 cheaper then a LS!?

 

Typically. But, LQ4's are cheaper than LQ9's as well.

 

I would hurry because the prices have doubled within the last 6-12 months. Now people are realizing that they are just as good as the ls1s and soon they will be going for close to ls1 prices.

I bet 5.3s will be doing the same eventually as well.

 

After my original post I saw one LQ4 on eBay for $525 plus freight, 2 others for $700 plus freight. Over 100k miles, but my 134k severely oil-change-neglected 2003 LQ4 still showed crosshatch in the cylinders.

The "cash for clunkers" Obomination is sure to cause the price for used engines to skyrocket.